Cap for a trailer van



FIG. 1 is a front perspective view of a cap for a trailer van showing my new design and shown in use on a trailer van;

FIG. 2 is a right side elevational view thereof, the left side being substantially a mirror image;

FIG. 3 is a front elevational view thereof; and

FIG. 4 is a top plan view thereof.

The broken lines in the drawing are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for a cap for a trailer van, as shown and described. 